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A028493
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a(0) = 16, a(n+1) = 3a(n) - (6-n)^2.
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0
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16, 12, 11, 17, 42, 122, 365, 1095, 3284, 9848, 29535, 88589, 265742, 797190, 2391521, 7174499, 21523416, 64570148, 193710323, 581130825, 1743392306, 5230176722, 15690529941, 47071589567, 141214768412
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,1
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REFERENCES
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Seen in a newspaper quiz.
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LINKS
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FORMULA
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a(n) = 6*a(n-1) - 12*a(n-2) + 10*a(n-3) - 3*a(n-4) for n > 3.
G.f.: (-65*x^3 + 131*x^2 - 84*x + 16)/((x - 1)^3*(3*x - 1)). (End)
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MAPLE
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(3^n + (5-n)*(6-n) + 1)/2;
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Mark Orr (mjo(AT)cns.ed.ac.uk)
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EXTENSIONS
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STATUS
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approved
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